1. Technical Field
This invention relates to a molded closure and the molding assembly for making the closure. More particularly, this invention relates to a molded closure having an auxiliary thread for removing incomplete injection runs that occur during the fabrication of such molded closures.
2. Description of the Related Art
The manufacture of molded polymeric closures is well known in the art. Injection molding techniques wherein a polymeric material is introduced into a molding assembly in order to form a molded closure are well known. Such molded polymeric closures often include substantially hollow cylindrical wall portions having smooth inner walls. A faulty run, or short shot, of the fabrication process sometimes results in the formation of a fragmentary closure containing no principal thread. Such a fragmentary closure is difficult to remove from the molding cavity due to the lack of engagable structure which may be used to pry the incomplete closure from the cavity. Therefore, the production of such a fragmentary closure often requires suspension of the process while non-process tools are used to pry the closure out of the molding cavity, thereby resulting in loss of production and increase in the likelihood of damage to the manufacturing equipment.
Current solutions to the problem of removing fragmented articles from a mold include molding structure into the polymeric article that must be engaged by a separate tool in order to remove the article. For example, U.S. Pat. No. 2,313,031 discloses a plastic container having a plurality of lugs molded therein. Upon the occurrence of a faulty run, the plunger of the molding assembly must be removed so that a separate tool may be introduced into the mold. The tool engages the lugs and then removes the article from the mold. However, none of the prior solutions provide a simple structure formed in the article that allows for the removal thereof from the mold cavity simply by removing the mold core.
Therefore, a molded closure formed with a core-and-cavity molding assembly is needed that includes a simple structure therein which provides engagement between the closure and the molding core, so that a fragmentary unit of such a closure may be removed from the molding cavity using only the engagement between the closure structure and the molding core.